无压渗透制备铝基复合材料及其性能的研究

Properties of Aluminium Matrix Composite by Pressureless Infiltration

采用无压渗透新工艺制备了Ａｌ２Ｏ３ 颗粒增强铝基复合材料，叙述了无压渗透工艺过程．通过金相显微镜、Ｘ射线衍射（ＸＲＤ） 、扫描电镜（ＳＥＭ） 、能谱（ＥＤＳ） 等手段，对（Ａｌ２ Ｏ３）ｐ／Ａｌ 的微观结构进行了分析；测试了铝基复合材料的力学及热物理性能．结果表明，铝基复合材料显微结构致密、渗透完全．在Ａｌ２Ｏ３ 与Ａｌ 的界面处，基体合金中的镁与增强剂Ａｌ２Ｏ３ 反应，原位生成ＭｇＡｌ２Ｏ４ 尖晶石晶体，其质量分数为４ ．１ ％ ．制造态复合材料的极限拉伸强度为３７８ ＭＰａ，拉伸模量为１２１ ．６ ＧＰａ，断裂延伸率为１ ．９６ ％ ，室温下导热系数为３０ ．３８ Ｗ／（ｍ·Ｋ） ，在５００ ℃时为３９ ．６７ Ｗ／（ｍ·Ｋ） ．在１０８０ ℃、２０ ｓ 的氧乙炔焰下，３ ｍ ｍ 厚的（Ａｌ２ Ｏ３）ｐ／Ａｌ 无烧蚀，试样表面完好，未破碎．

The Al 2O 3 particulates reinforced aluminium matrix composite is fabricated by a pressureless liquid metal infiltration process, which is examined by metalloscope, X ray diffraction(XRD),scanning electron microscope(SEM) and energy disperse spectrum(EDS).The microstructure of (Al 2O 3)p/Al is analysed with explanation given to the pressureless infiltration mechanism. Test results are also obtained for the mechanical properties and thermophysical properties of the composite. It is found that the spontaneous penetration is nearly perfect and the (Al 2O 3)p/Al composite has a dense microstructure. At the interface of (Al 2O 3)p/Al, there are MgAl 2O 4 Spinels which are formed by Mg reacting with Al 2O 3. The amount is about 4.1%. The ultimate tensile strength and modulus of the composite are 378 MPa and 121.6 GPa, respectively. The elongation at break is 1.96%.The thermal conductivities at room temperature and 500 ℃ are 30.38 W/(m·K) and 39.67 W/(m·K),respectively. The composite is non abration and was not broken for 20 s when heated by O 2 C 2H 2 flame at 1 080 ℃.